Das Projekt "Klimasimulation mit hoher Aufloesung fuer 10 Jahre" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Meteorologie durchgeführt. Objective: To evaluate the improvements of the present climate simulation as the model horizontal resolution increases. General Information: The present generation of general circulation models have a horizontal mesh size of between 600 and 300 km. This project addresses the issue of increased horizontal resolution and its main objective is to quantify the benefits of decreasing the grid size from 300 km to 100 km. It will advance our understanding of systematic errors and thereby lead to improvements in the models used for climate prediction. This study will also contribute to the CLIVAR programme by assessing the ability of high-resolution models to reproduce natural variability. The overall aim is to provide some of the quantitative information required to design the next generation of models that will be used to predict climate evolution due to the greenhouse gas radiative forcing for the assessment scenarios proposed within the IPCC framework. Three European models (the CNRM ARPEGE model, the MPI ECHAM4 model, and the UKMO Unified Model), each having a horizontal resolution of around 100 km, will be used for 10-year simulations of the present climate. This project follows on from the AMIP programme coordinated at the international level but performed with lower resolution models. As was the case for AMIP, boundary conditions will be provided by the observed sea surface temperatures for the period 1979-1988. The output of the 3 models will be organized as a common database, together with the ECMWF reanalysis fields which can be used as a reference. Indeed, two of the models use the same spectral truncation (T106) as the reanalysis. This database will be accessible by all European scientists. The study of the output will be organized, according to the specific knowledge of the participants. On the global scale, the simulated fields will be compared with ECMWF reanalyses, and also with fields obtained from a similar experiment, but with a standard resolution of 300 km. On the regional scale, the simulated fields will be compared by national meteorological services with data from the observation network. The surface fluxes of water, momentum and heat in the model exchange with the ocean will be investigated. The radiative fluxes at the top of the atmosphere, as well as at the surface, will be compared with the appropriate observation databases. The time evolution of the Alpine snow mantle, as estimated from the model circulations will be studied. The behaviour of the models over the ice sheets, their ability to force a limited area model, the simulation of blocking phenomena and of baroclinic waves will also be subjects of investigations. Prime Contractor: Centre National de la Recherche Scientifique, URA 1357, Groupe d Etude de l Atmosphere Meteorologique-Game; Zoulouse; France.
Das Projekt "European programme on prediction of climate variations on seasonal and interannual timescales" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Meteorologie durchgeführt. Objective: To quantify the predictability of the atmosphere on seasonal timescales over Europe and regions of the world where there may be European interests, and to test the skill of coupled models of the oceans, atmosphere and land surface, including data assimilation to provide initial conditions. General Information: The first objective is being pursued through a series of coordinated experiments using four European atmosphere models. These models are being run in ensemble mode over seasonal timescales using observed sea surface temperature and initial conditions from the ECMWF reanalysis period 1979-1994. This coordinated experimentation was underway at the beginning of the project, and is likely to be completed by the end of the first year. Diagnosis of results will take another year, and involves additional participants in the project. Complex numerical coupled models and ocean data assimilation techniques are being developed by five participants of the projects, and the ability to run hind cast experimentation will be possible by the second year of the project. Testing the skill of the numerical coupled model seasonal forecasts will begin in the second year of the project, through coordinated experimentation. Special attention will be given to the period 1990 onwards, since the ocean (especially the El Niqo region), was relatively well observed in that period. The skill of dynamically based seasonal forecasts will be compared with that obtainable by empirical prediction techniques. In addition the possibility of using these techniques (e.g. based on singular value decomposition) to correct, a posteriori, dynamical model biases will be investigated. Finally, close coordination between PROVOST and the monsoon project SHIVA will take place throughout the term of the project. As well as undertaking joint numerical experimentation, the SHIVA and PROVOST project will meet jointly each year. Prime Contractor: European Centre for Medium Range Weather Forecasts (ECMWF); Reading; United Kingdom.
Das Projekt "Untersuchung der direkten und indirekten Beeinflussung des Klimas durch anthropogene Spurengasemissionen" wird vom Umweltbundesamt gefördert und von Max-Planck-Institut für Meteorologie durchgeführt. Assessment of the regional distributions of the methane sources and source strengths will be achieved by 'inverse modelling' using global three-dimensional tracer transport models (TM2 and MOGUNTIA) and global observations. Atmospheric chemistry models will be further developed to be able to calculate distributions of sulfur species, the methane cycle, taking into account the role of CO, NOx and several hydrocarbons. The models will be based on the transport models TM2 and MOGUNTIA. A scheme for radiation calculation of atmospheric radiation for use in the three-dimensional climate model ECHAM will be developed. It will be based on the Morcrette scheme, which is used in the ECMWF operational weather prediction model. A code will be developed, which will treat the trace gases independently, and which will take into account the optical properties of aerosols. The scheme will be compared with detailed line-by-line calculations. A scheme for treating aerosols in the MOGUNTIA model will be developed, based on earlier work on the sulfur cycle. For use in the ECHAM model, a parametrization will be developed to describe the major aerosol influence on cloud microstructure and the optical properties of clouds. The ECHAM model will be applied to estimate the indirect cooling effect of ozone depletion. Also, the ECHAM model, coupled with a MPI ocean model, will be applied to study the climatic responses to perturbations in the radiative fluxes by alteration of concentrations of methane, sulfate and ozone. Programm modules developed by the individual participants will be implemented in ECHAM and several sensitivity studies performed. Results of these studies will be used to improve the TM2 and MOGUNTIA models. Model results will be validated through comparison with trace gas measurements from monitoring networks, precipitation statistics, precipitation chemical composition, aerosol climatologies from in-situ and remote sensing data, and with satellite data on aerosol and cloud optical depths and liquid water path. Much of the work will be done in collaboration with the Center for Clouds, Chemistry and Climate (C4) in the USA.